Multi-planar solid state amplifier

ABSTRACT

A solid state power amplifier (SSPA) system may include a radio frequency (RF) input, an RF waveguide split block, multiple monolithic microwave integrated circuit (MMIC) power amplifier modules, and/or a heat spreader. The power amplifier modules and RF waveguide may be distributed about the heat spreader in different planes. Furthermore, the power amplifier modules may be located on opposite sides of the heat spreader and nonplanar to the waveguide split block. A method for dissipating heat within an SSPA may include receiving an RF signal in a first plane, amplifying the RF signal in another plane, and combining the RF signal in yet another plane.

PRIORITY

This application is a continuation of U.S. patent application Ser. No.11/853,897, filed on Sep. 12, 2007, and entitled “SOLID STATE POWERAMPLIFIER WITH MULTI-PLANAR MMIC MODULES”, which is hereby incorporatedby reference.

FIELD OF INVENTION

The present invention relates to solid state power amplifiers. Moreparticularly, the invention relates to a solid state power amplifierhaving, for example, a waveguide split block construction that combinesmultiple monolithic microwave integrated circuit modules in multipleplanes.

BACKGROUND OF THE INVENTION

Solid state power amplifiers (SSPA's) are beneficial when used toamplify relatively weak radio frequency (RF) signals that arecommunicated with a satellite. The amplified RF signals are thencommunicated to additional electrical circuitry capable of converting,filtering, and otherwise adapting the original RF signals into signalsthat are recognizable as images, text, sound, or other useful media. Inaddition to satellite communication systems, SSPA's may be used inground-to-ground communication systems such as systems for localmultipoint distribution service (LMDS) or in other communicationssystems capable of achieving various objectives.

SSPA's are relatively reliable systems that include multiple monolithicmicrowave integrated circuit (MMIC) power amplifiers (PA) typicallymounted along a single plane to a heat sink structure that is alsoplanar in shape. The heat sink is capable of dissipating heat away fromthe MMIC's. MMIC's generate significant amounts of heat which must bedissipated through the heat sink in order to maintain reliability of theSSPA. Planar orientations of MMIC's also provide SSPA's of minimalvolume. However, such planar-shaped SSPA's often include anunnecessarily large footprint, which may prove ineffective for certainmarkets and applications.

For example, mobile satellite communications systems are often placedwithin vehicles, aircraft, ships, and other mobile transports. Suchmobile transports often require reliable communications equipment, yethave very limited and often awkwardly-shaped space available for theinstallation of such equipment. Many SSPA's capable of providingreliable amplification of RF signals to mobile transports simply wouldnot fit within such transports because of the large, planar size andfootprint of the SSPA's.

There is a need for a reliable and low-cost solid state power amplifierthat accommodates various size and shape requirements. The inventionaddresses this and other needs.

SUMMARY OF THE INVENTION

In accordance with an example of a solid state power amplifier (SSPA), aradio frequency (RF) input may be in communication with an RF waveguidesplit block, multiple monolithic microwave integrated circuit (MMIC)power amplifier modules, and a heat spreader. The RF waveguide splitblock may include an RF waveguide splitter and an RF waveguide combiner.The RF waveguide splitter is in communication with the RF input. TheMMIC power amplifier modules may be arranged in more than one plane, andare placed in communication with the RF waveguide split block. The heatspreader may be in thermal communication with the multiple MMIC poweramplifier modules.

An example of an SSPA may include a heat spreader having multiplesurfaces along multiple planes, and multiple MMIC power amplifiermodules in communication with the multiple surfaces of the heatspreader. Each of the multiple MMIC power amplifier modules may includea backing, a board, an MMIC, and a cover. The board may be mounted onthe backing, the MMIC may be mounted upon the backing, and the cover mayinsulate the MMIC. The backing may provide a thermal path from the MMIC,may include an RF waveguide feed for receiving RF signals, and mayinclude an RF waveguide launch for sending RF signals.

An example of a method for dissipating heat within an SSPA may includereceiving an RF signal, splitting the RF signal, amplifying multiple RFsignals, combining the multiple RF signals, generating heat frommultiple MMIC's, and/or dissipating the heat. Splitting the RF signalmay include splitting the RF signal along two planes into multiple RFsignals. Amplifying the multiple RF signals may include amplifying theRF signals with MMIC's arranged along two planes. Generating heat fromthe MMIC's may occur while amplifying the multiple RF signals.Dissipating the heat may include dissipating the heat generated from thetwo planes of MMIC's into a single heat spreader.

In accordance with an exemplary embodiment, power amplifier modules andan RF waveguide may be distributed about a heat spreader in differentplanes. Furthermore, the power amplifier modules may be located onopposite sides of the heat spreader and nonplanar to the waveguide splitblock. An exemplary method for dissipating heat within an SSPA mayinclude receiving an RF signal in a first plane, amplifying the RFsignal in another plane, and combining the RF signal in yet anotherplane.

In another exemplary embodiment, a power amplifier system includes awaveguide splitter, a waveguide combiner, and at least two poweramplifier modules. The power amplifier modules each have a MMIC.Furthermore, the power amplifier system includes a heat spreader with atleast four sides. The waveguide splitter connects to a first side, thewaveguide combiner connects to a second side, opposite the first side.The power amplifier modules are connected to a third and fourth side,respectively. In an exemplary embodiment, the first and second sides areperpendicular to the third and fourth sides.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

A more complete understanding of the present invention may be derived byreferring to the detailed description and claims when considered inconnection with the drawing figures, wherein like reference numbersrefer to similar elements throughout the drawing figures, and:

FIG. 1 shows a schematic diagram of an example of a solid state poweramplifier (“SSPA”);

FIG. 2 shows a perspective view of an example of a heat spreader mountedto an example of a base;

FIG. 3 shows a perspective view of an example of a heat spreader havinga single fluid space mounted to an example of a base;

FIG. 4 shows a perspective view of an example of a heat spreader havingmultiple fluid spaces mounted to an example of a base;

FIG. 5 shows a perspective view of an example of a heat spreader andwaveguide block mounted to an example of a base;

FIG. 6 shows a schematic diagram of an example of an eight-way radiofrequency (“RF”) waveguide splitter;

FIG. 7 shows a schematic diagram of an example of an eight-way RFwaveguide splitter having a driver module;

FIG. 8 shows a schematic diagram of an example of an eight-way RFwaveguide splitter having a converter module and local oscillator (“LO”)reference;

FIG. 9 shows a schematic diagram of an example of an eight-way RFwaveguide combiner;

FIG. 10 shows a perspective view of an example of multiple monolithicmicrowave integrated circuit (“MMIC”) power amplifier modules mounted toa waveguide split block and/or heat spreader which are in turn either orboth mounted to an example of a base;

FIG. 11 shows a perspective view of an example of an MMIC poweramplifier module;

FIG. 12 shows a perspective view of an example of an SSPA;

FIG. 13 shows a flow diagram of an example of a method for dissipatingheat within an SSPA;

FIG. 14 shows a flow diagram of an example of a method of dissipatingheat within an SSPA where the method includes driving an RF signal; and

FIG. 15 shows a flow diagram of an example of a method of dissipatingheat where the method includes referencing an RF signal and convertingan RF signal.

DETAILED DESCRIPTION

While exemplary embodiments are described herein in sufficient detail toenable those skilled in the art to practice the invention, it should beunderstood that other embodiments may be realized and that logicalelectrical and mechanical changes may be made without departing from thespirit and scope of the invention. Thus, the following detaileddescription is presented for purposes of illustration only.

In accordance with an example of a solid state power amplifier (SSPA),and with reference to FIG. 1, an SSPA 100 includes a radio frequency(RF) waveguide splitter 102, an RF waveguide combiner 104, a heatspreader 106, and multiple monolithic microwave integrated circuit(MMIC) power amplifier modules 108. The RF waveguide splitter 102 and RFwaveguide combiner 104 maybe arranged in any orientation within the SSPA100 and should operate as a single waveguide split block which serves topower combine the multiple MMIC power amplifier modules 108.Alternatives and/or additions to a split block may include any standardwaveguide splitter and combiner, coaxial splitters and combiners, andmicro-strip splitters and combiners (e.g., where lower frequencies arepreferred). The heat spreader 106 communicates with or is locatedbetween at least two planes of multiple MMIC power amplifier modules 108and serves to spread the heat received from MMIC's within the modules108. In one example of an embodiment, all components of the RF waveguidesplitter 102, RF waveguide combiner 104, heat spreader 106, and MMICpower amplifier modules 108 are housed within an electromagneticinterference (EMI) cover 110 that is installed over these electroniccomponents.

The RF waveguide splitter 102 includes an RF input 112 in communicationwith one or more RF channel splitters 114. The RF channel splitters 114evenly divide the RF signal into multiple separate RF signals andcommunicate the multiple RF signals to multiple RF signal outputs 116.Any number of RF channel splitters 114 and corresponding RF signaloutputs 116 maybe provided within the RF waveguide splitter 102. Forexample, in one embodiment, the RF waveguide splitter 102 may includeenough RF channel splitters 114 and RF signal outputs 116 in order tosplit at least one RF signal into between two and thirty-two or four andthirty-two separate RF signals, and, in one embodiment, eight separatesignals.

In an example of an embodiment of the RF splitter 102, a driver module118 may be placed in communication with the RF input 112. The driver 118serves in this example to increase the overall gain of the SSPA 100 sothat less RF input power is required to operate the SSPA 100. In anotherexample of an embodiment of the RF waveguide splitter 102, a localoscillator (LO) reference 120 is placed in communication with aconverter module 122 which is in turn placed in communication with theRF input 112. In an example of an SSPA that operates as a receiver, theconverter module 122 and LO reference 120 serve to convert the frequencyof the RF signal received through the RF input 112 to a lower and moremanageable intermediate frequency (IF).

In an example of an embodiment of an SSPA that operates as atransmitter, the RF input 112 may be an IF input, and the convertermodule 122 and LO reference 120 serve to convert the frequency of an IFsignal received through the IF input to a desired RF output signal. Inanother example of an SSPA, the entire LO chain of components requiredto produce an LO signal, such as multipliers and phase lock loops, mayreside within the SSPA. Where the entire LO chain of components resideswithin the SSPA, the LO chain can provide LO signal generation,multiplication, and/or referencing within the SSPA without the need ofreceiving an external LO reference signal.

Both the RF input 112, and the LO reference 120, when used incombination with the RF input 112, may extend through the housing ofboth the RF waveguide splitter 102 and the cover 110 of the SSPA 100. Asshown in FIG. 1, and with continued reference to the RF waveguidesplitter 102, the RF channel from the RF input 112 has been split by theRF a channel splitter 114 into two separate groups 115 and 117 of RFchannels. The two separate channel groups 115 and 117 form two separategroups of RF signal outputs 116. Each of the RF signal output 116 groupscommunicates with multiple MMIC power amplifier modules 108.

Each of the multiple MMIC power amplifier modules 108 includes an RFsignal feed 124, a monolithic microwave integrated circuit (MMIC) 126,and an RF signal launch 128. Each MMIC power amplifier module 108 alsoincludes a thermal channel 130. Each RF signal feed 124 is capable ofreceiving an RF signal from a corresponding RF signal output 116 of theRF waveguide splitter 102. The RF signal received by each RF signal feed124 is then communicated through the MMIC power amplifier module 108 toeach respective MMIC 126.

Each respective MMIC 126 then amplifies the RF signal and communicatesthe amplified RF signal to each respective RF signal launch 128. Duringamplification of each RF signal, each MMIC 126 generates heat. The heatgenerated during the RF signal is transferred through each respectivethermal channel 130 directly to the heat spreader 106.

The heat spreader 106 may be formed of a material having a high thermalconductivity. For example, the heat spreader 106 may be formed of amaterial such as aluminum or copper. The heat spreader 106 is capable ofreceiving heat through the thermal channels 130 associated with eachrespective MMIC power amplifier module 108 and dissipating the heatreceived through channels 130 throughout the heat spreader. In anexample of one embodiment, the heat spreader 106 may include one or morefluid spaces 132. The one or more fluid spaces 132 may be holes,chambers, or other formations within the heat spreader 106. The fluidspaces 132 may house any fluid such as air, water, oil, or other liquidor gas. Such fluid may flow through and/or circulate within the one ormore fluid spaces 132 in order to further dissipate heat of the heatspreader 106.

Multiple fluid spaces 132 may serve to reduce the weight of the heatspreader 106, and thus the weight of the SSPA 100, and provide acombined surface area greater than the surface area provided by only onelarge fluid space 132. The one or more fluid spaces 132 may be providedin any size, shape, number, orientation, arrangement, and or locationwithin the heat spreader 106 and/or other components of the SSPA 100 inorder to achieve any purpose consistent with the claimed invention. Forexample, a single fluid space 132 may be strategically located tocommunicate with a single MMIC power amplifier module 108, and thusdissipate the heat from that single module 108 into a space within theheat spreader 106 that appropriately distributes the heat within atleast the heat spreader 106 away from other hot areas of the heatspreader 106.

As indicated previously, any number of MMIC power amplifier modules 108may be provided in an SSPA 100. The total number of MMIC power amplifiermodules 108 may correspond with the total number of RF signal outputs116 of the RF waveguide splitter 102. Similarly, the total number ofMMIC power amplifier modules 108 may correspond with a total number ofcorresponding inputs 134 located within the RF waveguide combiner 104.Each of the multiple inputs 104 communicates with a channel that iscombined with at least one other channel using one or more RF channelcombiners 136. The multiple RF channel combiners 136 may further combinemultiple RF signals into ultimately as few as a single RF signal. Thesingle RF signal may then be communicated from the combiners 136 througha channel to an RF signal output 138.

The multiple RF signal inputs 134 receive the corresponding RF signalsfrom the RF signal launches 128 of each respective MMIC power amplifiermodule 108. The received and amplified RF signals are then transferredfrom each RF input 134 and combined through the RF channel combiners 136to provide a combined RF signal to the output 138 of the RF waveguidecombiner 104. The RF signal output 138 may extend through the housing ofboth the RF waveguide combiner 104 and the cover 110 of the SSPA 100.

As with the two groups 115 and 117 of RF signal outputs 116 of the RFwaveguide spreader 102, the RF signal inputs 134 are separated into twoseparate groups 135 and 137 within the RF waveguide combiner 104. Thetwo separate groups of both the RF signal outputs 116 (that is, groups115 and 117) and the RF signal inputs 134 (that is, groups 135 and 137)correspond with two separate groups of MMIC power amplifier modules 108.The two separate groups of the MMIC power amplifier modules 108 arelocated on separate planes, and, in the example shown in FIG. 1, arelocated on opposite sides of the heat spreader 106. By locating orarranging at least two separate groups of MMIC power amplifier modules108 on opposite sides of a single heat spreader, the overall size andshape of the SSPA 100 may be modified from a traditional shape to anon-traditional shape. For example, some traditionally-shaped SSPA'shave been relatively flat and long amplifiers having a relatively largefootprint when placed upon a surface. In contrast, the SSPA 100 may bearranged in a variety of sizes and shapes such as a cube, parallelogram,hexagon, octagon, or other multi-surface structure. Although it mayprovide an amplifier with a volume larger than some traditionalamplifiers, the multi-surface shape of an SSPA 100 may be configured tohave a much smaller footprint when placed upon a surface thantraditional flat SSPA's. The SSPA 100 may also be arranged in otherorientations in order to modify the dimensions of the SSPA 100 for aparticular purpose. For example, the SSPA 100 may be configured toprovide dimensions capable of allowing the SSPA 100 to be placed withina mobile transport such as a vehicle, aircraft, or ship.

The elements described above with reference to FIG. 1 will now bedescribed in greater structural and functional detail with reference tothe following figures.

Referring to FIG. 2, an example of a heat spreader 106 is shown mountedto a base 140 of an SSPA 100. The heat spreader 106 maybe a single solidpiece of thermally conductive material, such as aluminum or copper, aspreviously described, or any other suitable conductive material. Theheat spreader 106 may be mechanically or otherwise secured or attachedto the base 140. The cover 110 may be mechanically or otherwise attachedto the base 140 such as by sending fasteners through multiple holes 142in order to pull the bottom surface of the cover 110 against the topsurface of the base 140. The base 140 may form the floor of the SSPA 100to which the cover 110 (FIG. 1) may be attached in order to encompassthe electronics within the SSPA 100. The base 140 may be formed of anymaterial consistent with the purposes of the claimed invention, such asa metal, alloy, metal-alloy, polymer, ceramic, or other material. Likethe cover 110, the base 140 will, in one embodiment, be environmentallysealed to prevent, for example, moisture or dust from getting into theelectronics inside the cube and will serve to prevent electromagneticinterference with the electronics within the SSPA 100 and theenvironment surrounding the SSPA 100. The cover 110 may be formed of anynumber of separate components and may be attached to, secured to,combined with, or formed with any other the components of thisdisclosure in any enabling manner.

Referring to FIG. 3, an example of an embodiment of a heat spreader 106is shown mounted on a base 140. Base 140 may, for example, have multipleholes 142 for attachment of a cover 110 to the base 140. The example ofthe heat spreader 106 includes a single large fluid space 132 throughthe central long axis of the heat spreader 106. The single fluid space132 may be configured to reduce the weight and further improve thethermal design of the heat spreader 106 by providing an alternate mediumof heat transfer within the heat spreader 106. The single hole 132 wouldalso be very simple to manufacture using molding, drilling, boring,and/or other methods. A corresponding hole may be located within thecover 110 and directly over the single fluid space 132 in order toprovide further heat transfer from the heat spreader 106 to theenvironment outside of the SSPA 100. Additionally and/or alternatively,all or a portion of the single fluid space 132 maybe covered or cappedso that a fluid such as air, water, oil, and/or other liquid or gas maybe contained and flow within the heat spreader 106 and/or the chamberformed between the enclosed cover 110 and base 140.

Referring to FIG. 4, an example of an embodiment of a heat spreader 106is shown mounted to a base 140. Base 140 may, for example, have multipleholes 142 for attachment of the base 140 to a cover 110. The multiplefluid spaces 132 of FIG. 4 may be manufactured using any conventionaltechnique such as those described with reference to the heat spreader106 of FIG. 3. In this example of a heat spreader 106, multiple fluidspaces 132 are shown formed through the long axis of the heat spreader106. The multiple fluid spaces 132 of the embodiment described withreference to FIG. 4 may be configured to provide approximately the sameamount of fluid space volume as the single fluid space 132 describedwith reference to FIG. 3. However, in one example of an embodiment themultiple smaller fluid spaces 132 described with reference to FIG. 4 mayprovide a total combined surface area that interacts with the insidesurface of the heat spreader 106 that is greater than the total surfacearea of the single fluid space 132 described with reference to FIG. 3.Because of the increased amount of surface area, the heat spreader 106may better transfer and/or dissipate heat through the various surfacesof the multiple fluid spaces 132 and into the fluid located within eachrespective space 132.

Similar to the embodiment described with reference to FIG. 3, the heatspreader 106 described with reference to FIG. 4 may include open,partially-closed, and/or fully-closed fluid spaces 132 capable ofreceiving heat from the heat spreader 106, transferring or dissipatingheat from the fluid spaces 132 into the larger environment within theSSPA 100, and/or transferring or dissipating heat out one or more holeswithin the cover 110 of the SSPA 100 and into the environmentsurrounding the SSPA 100. Manufacturers desiring to isolate the heatedfluid from the electrical components within the SSPA 100 may install anenvironmental seal, such as an o-ring, between the fluid spaces 132 andthe cover 110. The environmental seal acts as a fluid barrier betweenthe electronics within the SSPA 100 and both the external environmentand the channel formed between the fluid spaces 132 and the cover 110.The environmental seal also serves to channel heated fluid from thefluid spaces 132 to the hole(s) formed within the cover 110 so that thefluid may escape to the environment surrounding the SSPA 100.

Referring to FIG. 5, an example of an embodiment of a heat spreader 106is mounted to a base 140. Base 140 may, for example, have multiple holes142 for attachment of a cover 110 to the base 140. In an example of anembodiment, an SSPA 100 includes a wave guide split block 144. Althoughthe split block 144 may have any suitable number of channels, in thisexample embodiment the SSPA 100 includes an eight-way waveguide splitblock 144. An eight-way waveguide split block 144 includes an RFwaveguide splitter 102 and an RF waveguide combiner 104. In one exampleembodiment, the RF waveguide splitter 102 and RF waveguide combiner 104are separated from each other and located on and attached to oppositesides of the heat spreader 106. Both the RF waveguide splitter 102 andthe RF waveguide combiner 104 are formed of metal or similar material.

Both the RF waveguide splitter 102 and RF waveguide combiner 104 areformed of split blocks capable of being separated into a first section146 and a second section 148. The first section 146 and the secondsection 148 both include grooves within the inner surface of thesections 146 and 148 which, when both sections 146 and 148 are combined,form various splitting and combining channels. The channels form a paththrough which RF signals may travel between the first section 146 andthe second section 148 to either be split into multiple signals withinthe splitter 102 or to be combined from multiple RF signals into fewerRF signals in the combiner 104. In one embodiment, the channels of boththe splitter 102 and combiner 104 are symmetrical with each other suchthat the splitter 102 and combiner 104 are in phase with each other.Although other shapes may be used, the cubic shape of the heat spreader106 and cubic orientation of the splitter 102 and combiner 104 permitthe channel networks of both the splitter 102 and combiner 104 to be inphase with each other. Thus, other regular shapes with similaradvantages may also be used advantageously.

The splitter 102 includes at its top surface, between the first section146 and the second section 148, an RF signal input 112. The RF waveguidesplitter 102 also includes along its front and back surfaces two sets offour channels each terminating at an RF signal output 116. The RFwaveguide combiner 104 similarly includes an RF signal output 138 at itstop surface between first section 146 and second section 148. The RFwaveguide combiner 104 also includes along its front and back surfacestwo sets of four channels originating at multiple RF signal inputs 134.

The first section 146 and second section 148 of both the splitter 102and combiner 104 may be formed as structurally-identical components.Forming these sections as identical parts may be advantageous tomanufacturers who desire to simplify the SSPA 100 design and increasethe volume of preparing split block parts. By increasing the volume ofrecurring and replaceable parts within the SSPA 100, a manufacturer candecrease the cost to manufacture the SSPA 100.

Referring to FIG. 6, the eight-way RF waveguide splitter 102 shownmechanically and described with reference to FIG. 5 is shown in FIG. 6in schematic representation. The eight-way RF waveguide splitter 102includes an RF signal input 112 that communicates with a series of RFchannel splitters or dividers 114 which communicate with each other tosplit one or more RF signals into multiple RF signals. Ultimately, themultiple RF signals are split by the RF channel splitters 114 into eightseparate RF signals that are communicated to a first plane 150 of fourRF signal outputs 116 and a second plane 152 of four RF signal outputs116. The first plane 150 of four RF signal outputs 116 is shown in FIG.5 on the front surface of the RF waveguide splitter 102. The secondplane 152 of the four signal outputs 116 is located on the back surfaceof the RF waveguide splitter 102 shown in FIG. 5. A total of sevendifferent RF channel splitters 114 are used to split a single RF signalinto eight separate signals as shown in the example of the RF waveguidesplitter 102 of FIG. 6.

Referring to FIG. 7, another example of an RF waveguide splitter 102includes the components described with reference to FIG. 6 and alsoincludes an optional driver module 118. As described previously withreference to FIG. 1, the driver module 118 may be used in conjunctionwith the RF signal input 112 and the eight-way waveguide splitter 102 toincrease the overall gain of the SSPA 100 so that less RF input power isrequired to operate the SSPA 100.

Referring to FIG. 8, another example of an eight-way splitter 102 mayinclude the components described with reference to FIG. 6 and anadditional converter module 122 in communication with an LO reference120. As previously described with reference to FIG. 1, the convertermodule 122 and LO reference 120 convert the frequency of the inputted RFsignal from input 112 to a lower and more manageable intermediatefrequency (IF) or, alternatively, from an IF signal to an RF signal.

Referring to FIG. 9, the example of an embodiment of an eight-waywaveguide combiner 104 described with reference to FIG. 5 is shown in aschematic representation. The eight-way waveguide combiner 104 includesa common output port 138 in communication with multiple RF channelcombiners 136 which communicate with each other and with multiple RFsignal inputs 134 (FIG. 1). The eight RF signal inputs 134 are separatedinto two sets of four RF signal inputs 134 along two planes. A firstplane 154 includes four RF signal inputs 134 and a second plane 156includes the other four signal inputs 134. The first plane 154 includingfour RF signal inputs 134 is shown on the front surface of the eight-waywaveguide combiner 104 of FIG. 5, while the second plane 156 of theremaining four RF signal inputs 134 is located on the back side of theeight-way combiner waveguide combiner 104 of FIG. 5.

The eight RF signal inputs 134 of the first plane 154 and second plane156 of the eight-way waveguide combiner 104 combine eight received andamplified RF signals through a series of seven RF channel combiners inorder to provide a single amplified RF signal that is communicated tothe common port output 138.

Referring to FIG. 10, the example of an embodiment of an eight-waywaveguide split block 144 of FIG. 5 is shown with eight MMIC poweramplifier modules 108 located on the front side and back side of thesplit block 144 and the heat spreader 106. The eight separate MMIC poweramplifier modules 108 are split into two groups of four modules 108 withfour MMIC power amplifier modules 108 located on the front side of theblock formed by the waveguide split block 144 and four MMIC poweramplifier modules 108 located on the back side of the waveguide splitblock 144. Each of the separate MMIC power amplifier modules 108 may beattached to the waveguide split block 144, that is either to the firstsection 146 or second section 148 of either of the splitter 102 orcombiner 104, and/or may be attached to the heat spreader 106. Each ofthe MMIC power amplifier modules 108 aligns a feed 124 with acorresponding RF signal output 116 (FIG. 1) on the splitter 102 andaligns a launch 128 (FIG. 1) with the corresponding RF signal input 134(FIG. 1) of the combiner 104.

Further, each of the MMIC power amplifier modules 108 aligns itsrespective thermal path 130 directly between the MMIC 126 of the module108 and the heat spreader 106. Thus, heat may transfer directly fromeach MMIC 126 of module 108 and the heat spreader 106. By providing adirect thermal path 130 between the MMIC 126 and the heat spreader 106,the heat transfer and dissipation is localized and controlled within theheat spreader 106 and any fluid spaces 132 with which the heat spreader106 communicates. By controlling the flow of heat within the SSPA 100,the heat generated from the MMIC's 126 during amplification of the RFsignals will not interfere with other necessary electrical operationswithin the SSPA 100. Thus, by controlling heat flow and dissipationthrough the heat spreader 106, the reliability of the SSPA 100 isincreased.

Referring to FIG. 11, a single MMIC power amplifier module 108 is shown.In this example of an embodiment of an MMIC power amplifier module 108 abacking 158 resides adjacent a board 160. The board 160 is mounted uponthe backing 158, may be a printed wiring board (PWB) or similarstructure, and may include, among other electrical components, an MMIC126. The board 160 may also include a DC connector 161 or othercomponents that control power input to the MMIC 126. The MMIC 126 andboard 160 are adjacent a cover 162. The MMIC 126 may be mounted upon theboard 160 (e.g., when the MMIC is packaged with the board 160) and/orthe backing 158. Mounting the MMIC 126 directly to the backing 158 mayprovide a better thermal communication path between the MMIC 126 and thebacking 158. The cover 162 may insulate and/or secure the MMIC 126 onthe MMIC power amplifier module 108.

The backing 158 may operate as a chassis formed of athermally-conductive material such as light-weight aluminum and/orheavier copper. The backing 158 is an optional component that may bereplaced by any other surface of one or more structures of the SSPA 100,such as the heat spreader 106, splitter 102, and/or combiner 104. Theboard 160 may be Rogers 4003 or 6002 material, a ceramic board, amicrowave board, and/or a DC FR4 poly-board. The cover 162 may be formedof aluminum, zinc, liquid crystal polymer (LCP) to form a hermetic-likecase, and/or a non-thermal plated plastic that operates as an RF shield.Other similar materials may be used as appropriate.

The backing 158 may provide a thermal path between the MMIC 126 and theheat spreader 106. It is important, but not necessary, that the backing158 be placed into direct contact with the heat spreader 106, as doingso it will provide the shortest thermal path between the MMIC 126 andthe heat spreader 106. The backing 158, the board 160, and/or any otherportion of the MMIC power amplifier module 108, may include an RFwaveguide feed 124 for receiving RF signals from a corresponding RFsignal output 116 (FIG. 1) and/or may include an RF waveguide launch 128for sending RF signals to a corresponding RF signal input 134 (FIG. 1).The backing 158, board 160, and/or cover 162 may include one or moreattachment features 164 such as holes for securing each respectivecomponent of the backing 158, board 160, and/or cover 162 to each otherand/or to other structures within the SSPA 100. For example, themultiple holes 164 on the cover 162 may house screws that secure thecover 162 to the board 160 and/or backing 158. As another example, themultiple holes 164 on the backing 158 may secure the entire MMIC poweramplifier module 108 to both the RF waveguide splitter 102 and combiner104 as shown and described in FIG. 10 and/or to the heat spreader 106.

Each MMIC power amplifier module 108 may be manufactured independent ofany other module 108. Thus, a set of four MMIC power amplifier modules108 need not be assembled as a single piece. By assembling and/ormanufacturing each module 108 independent of any other, themanufacturability and scalability of the SSPA 100 is increased. Forexample, the SSPA 100 may include more than eight MMIC power amplifiermodules 108 within the SSPA 100. In this instance, a manufacturer needonly provide additional MMIC power amplifier modules 108 along with acorrespondingly-sized heat spreader 106 and waveguide split block 144.Thus, the scale of the SSPA 100 may be easily changed using separateMMIC power amplifier modules 108. The manufacturer may choose to combinemore or less of the MMIC power amplifier modules 108 to achieve more orless output power for the SSPA 100. As indicated above, by increasing ordecreasing the total number of MMIC power amplifier modules 108, thesplit block 144, heat spreader 106, and housing 110 and 140 would needto be scaled appropriately to be scaled to accommodate the scale ofmodules 108.

Further, the manufacturing yield of separate MMIC power amplifiermodules 108 will be improved since each module 108 can be screened ortuned before and/or after being integrated into the SSPA 100. Formodules 108 which need to be replaced and/or repaired after beingintegrated into the SSPA 100, a manufacturer may replace or repair thatsingle module 108 without having to replace or repair the remainingmodules 108 on a given plane of the SSPA 100. For example, amanufacturer may replace and/or repair all or a portion of a singlemodule 108 by removing the module 108 from the split block 144 orremoving the cover 162 of the module 108. After the cover 162 of themodule is removed, the manufacturer can access, trouble shoot, tune, addto, remove from, and/or rework all of the electronics within the module108 to obtain optimum SSPA 100 performance while the remainder of themodule 108 is attached to the split block 144.

In other examples of an SSPA 100, each MMIC power amplifier module 108may include multiple MMIC's 126. Providing multiple MMIC's 126 on asingle MMIC power amplifier module 108 will enable a manufacturer toreduce the number of MMIC power amplifier modules 108 within the SSPA100. Since each MMIC power amplifier module 108 may require additionalspace for screws, backings, and/or other mechanical and/or electricalconnections, by reducing the number of MMIC power amplifier modules 108within an SSPA 100, the total volume of the SSPA 100 should also bereduced. For example, an SSPA 100 may include only two MMIC poweramplifier modules 108 on opposite sides of the SSPA 100, with each MMICpower amplifier module 108 having between two and sixteen MMIC's 126.Further, each MMIC power amplifier module 108 may have an additionaldriver MMIC in series with one or more power amplifier MMIC's 126, inorder to increase the overall gain of the MMIC's 126.

Referring to FIG. 12, an example of an embodiment of an SSPA 100 isshown with a cover 110 mounted to a base 140. The cover 110 includes anRF signal input 112 and an RF signal output 138 on its top surface. TheRF signal input 112 corresponds with the location of the RF signal input112 of the RF waveguide splitter 102 described with reference to FIG.10. Similarly, the RF signal output 138 corresponds in location with theRF signal output 138 of the RF waveguide combiner 104 described withreference to FIG. 10. The RF signal input 112 and output 138 may belocated on any surface of the SSPA 100 as desired for a particularimplementation. For example, although the input 112 and output 138interfaces are both shown on the top side in FIG. 12, different routingwithin the split block 144 would allow the input 112 and/or output 138to be routed through the bottom of the SSPA 100, that is through thebase 140. With additional straight through waveguide split block pieces,the input 112 and/or output 138 could be routed to the front, back,right, and/or left sides of the cover 110. Inputs 112 and/or outputs 138which extend through the sides of the cover 110 may be used incombination with a two piece cover 110 to increase access for attachingthe additional input 112 and output 138 waveguide pieces.

Referring to FIG. 13, a method of using an SSPA 100 may include thefollowing steps: receiving and/or inputting an RF signal 166, splittingthe RF signal 168, amplifying the RF signal 170, combining the RF signal172, and sending or outputting the RF signal 174. Additionally, themethod may include generating heat 176 while amplifying the RF signal170 and then dissipating the heat 178. Receiving and/or inputting the RFsignal 166 may occur through an RF signal input 112. Splitting the RFsignal 168 may include splitting the RF signal into multiple RF signalswith outputs along two planes, such as into the first plane 150 and thesecond plane 152 with reference to FIG. 6. Amplifying the RF signal 170may include amplifying multiple RF signals with multiple MMIC's 126arranged along two separate planes, for example, as described withreference to FIG. 10. Combining the RF signal 172 may include combiningthe multiple amplified RF signals from multiple RF signal inputs 134into fewer RF signals, such as a single RF signal to be sent to RFsignal output 138. The combining may occur in a separate plane from thesplitting. Generating heat 176 may include generating heat from multipleMMIC's 126 while amplifying the multiple RF signals. Dissipating heat178 may include dissipating heat that is generated from the two separateplanes of MMIC power amplifier modules 108 into a single heat spreader106. Dissipating heat 178 may also include dissipating the heat into oneor more heat spreaders 106 having one or more fluid spaces 132 intowhich the heat may be further dissipated.

Referring to FIG. 14, the method described with reference to FIG. 13 maybe modified to include the step of driving the power of the RF signal180 after the step of receiving an RF signal 166. Referring to FIG. 15,the method described with reference to FIG. 13 may be modified toinclude the steps of referencing the RF signal 182 and then convertingthe RF signal 184 after the step of receiving an RF signal 166.Alternatively or additionally, the method may include the steps ofreferencing an IF signal and then converting the IF signal to an RFsignal.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any element(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as critical, required, or essentialfeatures or elements of any or all the claims. As used herein, the terms“includes,” “including,” “comprises,” “comprising,” or any othervariation thereof, are intended to cover a non-exclusive inclusion, suchthat a process, method, article, or apparatus that comprises a list ofelements does not include only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Further, no element described herein is requiredfor the practice of the invention unless expressly described as“essential” or “critical.”

1. A solid state amplifier system comprising: an radio frequency (RF)waveguide split block including an RF waveguide splitter and an RFwaveguide combiner, wherein the RF waveguide splitter is incommunication with an RF input; a first monolithic microwave integratedcircuit (MMIC) arranged in a first plane and a second MMIC arranged in asecond plane, wherein the first plane is not coplanar with the secondplane, and wherein the first MMIC and the second MMIC are placed incommunication with the RF waveguide split block; and a heat spreaderhaving a first surface and a second surface, wherein the first surfaceis in thermal communication with the first MMIC, wherein the secondsurface is in thermal communication with the second MMIC, and whereinthe first surface is in a different plane than the second surface. 2.The system of claim 1, wherein the first MMIC is part of a first poweramplifier module, and the second MMIC is part of a second poweramplifier module, wherein the first power amplifier module is in contactwith the first surface of the heat spreader and wherein the second poweramplifier module is in contact with the second surface of the heatspreader.
 3. The system of claim 2, wherein the first and second poweramplifier modules are power combined to each other through the RFwaveguide split block.
 4. The system of claim 3, wherein each of thefirst and second power amplifier modules includes an RF feed and an RFlaunch, wherein the RF waveguide splitter includes first and secondsplitter outputs that each send RF signals to the corresponding RF feedof the respective first and second power amplifier modules, and whereinthe RF waveguide combiner includes first and second combiner inputs thateach receive RF signals from the corresponding RF launch of thecorresponding first and second power amplifier modules.
 5. The system ofclaim 4, wherein the RF waveguide splitter splits at least one RF signalinto four to thirty-two separate RF signals, and wherein the RFwaveguide combiner combines four to thirty-two separate RF signals intoat least one RF signal.
 6. The system of claim 4, further comprising anelectromagnetic interference cover over the RF waveguide split block,the first and second power amplifier modules, and the heat spreader,wherein the heat spreader communicates with at least one fluid space,wherein the first power amplifier module includes a first printed wiringboard (PWB) attached to the first MMIC, and wherein the second poweramplifier module includes a second PWB attached to the second MMIC.
 7. Asolid state amplifier comprising: a heat spreader having first, second,third, and fourth surfaces along different planes; a first monolithicmicrowave integrated circuit (MMIC) in thermal communication with thesecond surface of the heat spreader; and a second MMIC in thermalcommunication with the third surface of the heat spreader; wherein thefirst MMIC is part of a first power amplifier module that is in contactwith said second surface of the heat spreader, and wherein the secondMMIC is part of a second power amplifier module that is in contact withthe third surface of the heat spreader.
 8. The solid state amplifier ofclaim 7, wherein the first and second power amplifier modules eachcomprise: a backing; a printed wiring board mounted upon the backing;and a cover at least partially covering at least one of the first andsecond MMIC; wherein the backing provides a thermal path from at leastone of the first and second MMIC to the heat spreader; wherein thebacking includes a radio frequency (RF) waveguide feed for receiving RFsignals; and wherein the backing includes an RF waveguide launch forsending RF signals.
 9. The solid state amplifier of claim 7, wherein thesurfaces of the heat spreader, including at least the first, second,third, and fourth surfaces, together form an exterior prism shape forthe heat spreader.
 10. The solid state amplifier of claim 9, wherein theexterior prism shape is one of a rectangular prism, a cubic prism, ahexagonal prism, a parallelogram prism, and an octagonal prism.
 11. Thesolid state amplifier of claim 7, wherein the first and second MMIC arein direct contact with the backing.
 12. The solid state amplifier ofclaim 7, wherein the first and second power amplifier modulesindividually communicate with an RF waveguide splitter and an RFwaveguide combiner.
 13. A method for amplifying a radio frequency (RF)signal within a solid state amplifier, the method comprising: receivingan RF signal; splitting the RF signal into multiple RF signals andoutputting a first set of the multiple RF signals for use in a firstplane and outputting a second set of the multiple RF signals for use ina second plane; amplifying the first set of the multiple RF signals witha first amplifier component located in the first plane and amplifyingthe second set of the multiple RF signals with a second amplifiercomponent located in the second plane, and combining the first andsecond sets of the multiple RF signals in a different plane than theplane used for splitting the RF signal.
 14. The method of claim 13,further comprising the steps of dissipating heat from the firstamplifier component and second amplifier component into a single heatspreader.
 15. The method of claim 14, wherein said solid state amplifieris a solid state power amplifier.
 16. The method of claim 15, furthercomprising: dissipating the heat in the single heat spreader into afluid space, and converting a signal between an intermediate frequency(IF) signal and an RF signal.
 17. The method of claim 13, wherein thefirst and second amplifier components each comprise at least onemonolithic microwave integrated circuit (MMIC).
 18. A three dimensionalsolid state amplifier comprising: a waveguide splitter in a first plane;a waveguide combiner in a second plane; and a first amplifier componentin a third plane and a second amplifier component in a fourth plane,wherein each of the first and second amplifier components individuallycomprise active components configured to amplify a radio frequency (RF)signal; wherein the waveguide splitter is connected in communicationwith inputs of the first and second amplifier components; wherein thewaveguide combiner is connected in communication with outputs of thefirst and second amplifier components; wherein the first, second, third,and fourth planes are not co-planar; and wherein the first and secondplanes are not parallel to either of the third and fourth planes.
 19. Athree dimensional solid state amplifier comprising: a radio frequency(RF) signal splitter in a first plane; an RF signal combiner in a secondplane; and a first amplifier component in a third plane and a secondamplifier component in a fourth plane, wherein each of said first andsecond amplifier components comprises active components configured toamplify an RF signal; wherein the RF signal splitter is connected incommunication with the first and second amplifier components; whereinthe RF signal combiner is connected in communication with the first andsecond amplifier components; and wherein the first, second, third, andfourth planes are arranged about a central axis, and parallel to thecentral axis.
 20. The three dimensional solid state amplifier of claim19, wherein the central axis is defined by the intersection of aperpendicular plane from the middle of each of the RF signal splitter,the RF signal combiner, the first amplifier component and the secondamplifier component.
 21. The three dimensional solid state amplifier ofclaim 19, wherein a heat spreader has an exterior shape of a prism,wherein a prism is a three dimensional figure that has multiple sidesand has two parallel and congruent bases in the shape of polygons, andwherein the RF signal splitter, the RF signal combiner, the firstamplifier component and the second amplifier component are arrangedabout the multiple sides of the prism.
 22. A power amplifier comprising:a first power amplifier module in a first plane; a second poweramplifier module in a second plane; and a signal splitter in a thirdplane, wherein an RF signal is communicated from the signal splitter tothe first and second power amplifiers, and wherein the RF signal iscommunicated from the first and second power amplifiers to a signalcombiner in a fourth plane.